CASTINE, Maine – The University of Maine Cooperative Extension will host a tour of Castine’s historical trees from 10 a.m. to noon Friday, June 17, at the Post Office on Main St. in Castine.¬† Jan Ames Santerre, with the Maine Forest Service, will lead a tour of historic elms and other noteworthy tress found in Castine.¬† The event is free and open to the public with pre-registration requested. For more information or to register before June 13, call 800-287-1471.